Photonic systems are presently used in a variety of applications and devices to communicate information using light (optical) signals. Photonic systems typically include photonic integrated circuits (PICs), which are analogous to electronic integrated circuits in that they integrate multiple components into a single material where those components operate using light only or a combination of light and electricity. A typical PIC has a combination of electrical and optical functionality, and can include light transmitters (light sources) and light receivers (photodetectors), as well as electrical wiring and like components that serve to generate and carry electrical signals for conversion to optical signals and vice versa.
A PIC includes one or more optical waveguides that carry light in analogy to the way metal wires carry electricity in electronic integrated circuits. Just as the electricity traveling in the wires of an electronic integrated circuit carries electrical signals, the light traveling in the waveguides of a PIC carries optical signals.
To transmit the optical signals from the PIC to a remote device, the optical signals carried by a waveguide in the PIC need to be transferred or “optically coupled” to a corresponding optical fiber connected to the remote device. Coupling light from a planar waveguide to an optical fiber is achieved either through the surface of the PIC via surface corrugated gratings or via embedded total internal reflection mirrors, or from the edge via proximity coupling or edge coupling, also referred to as “butt coupling.”
Current edge coupling techniques involve forming a permanent bond between the optical fibers and the waveguides. Thus, there is an unresolved need for improved edge coupling.